NETSTAT.exe

Display current TCP/IP network connections and protocol statistics.

Syntax
NETSTAT [options] [-p protocol] [interval]
Key -a Display All connections and listening ports.
-e Display Ethernet statistics. (may be combined with -s)
-n Display addresses and port numbers in Numerical form.
-r Display the Routing table.
-o Display the Owning process ID associated with each connection.
-b Display the exe involved in creating each connection or listening port.*
-v Verbose - use in conjunction with -b, to display the sequence of components involved for all executables.
-p protocol
Show only connections for the protocol specified;
can be any of: TCP, UDP, TCPv6 or UDPv6.
If used with the -s option then the following protocols
can also be specified: IP, IPv6, ICMP,or ICMPv6.
-s Display per-protocol statistics. By default, statistics are
shown for IP, IPv6, ICMP, ICMPv6, TCP, TCPv6, UDP, and UDPv6;
(The v6 protocols are not available under 2k and NT4)
The -p option can be used to display just a subset of these.
interval Redisplay statistics, pausing interval seconds between
each display. (default=once only) Press CTRL+C to stop.

* Where available this will display the sequence of components involved in creating the connection or listening port. (Typically well-known executables which host
multiple independent components.) This option will display the executable name in [ ] at the bottom, with the component it called on top, repeated until TCP/IP is reached. The -b option
can be time-consuming and will fail unless you have sufficient permissions.

"Once you're on the network, you can do a command called NetStat - Network Status - and it lists all the connections to that machine. There were hackers from Denmark, Italy, Germany, Turkey, Thailand ..." ~ Gary McKinnon